Regenerator matrix



Nov. 4, 1969 R. w. GUERNSEY ET AL 3,476,174

REGENERATOR MATRIX INvENTORs /Pbezz 7). @azemse Filed Deo. 29. 1967United States Patent C U.S. Cl. 165-9 A' 5 Claims ABSTRACT oF THEDISCLOSURE An annular matrix for a radial-flow regenerator has rims ateach end of the matrix with stiffeners connecting the rims. A heattransfer segment mounted between each pair of stiffeners embodiespermeable heat transfer material (shim packs) and labyrinth'seal platesextending from the surface of the shim packs. Thermal deflection of thesegment is minimized by beams extending across the matrix from rim torim and a bridge intermediate the rims connecting the beams. The bridgeis brazed to the seal elements and shim packs. Thebeams have low thermaldeflection and thus, through the bridge, control the thermal deflectionof the heat transfer material and seal elements.

Our invention relates to rotary'regenerators and particularly to animproved structureof the matrix of such regenerators effective to reducethermal-distortion of the matrix. It is well known that such matricestend to distort in operation because of the considerable temperaturedifference between the hot and cold faces of the matrix. Particularly inapplications of regenerators in which there is a substantial pressuredifference between the two fiuids, it is important to seal as closely asfeasible to the matrix so as to minimize escape of the high pressure uidinto the low pressure area.

Our invention is directed to providing a matrix which, by virtue ofsimple and feasible structure, substantially reduces the deflection ofthe matrix due to temperature differences so that the parts whichcooperate with fixed seals in the regenerator better accomplish thesealing function, provides for much closer spacing of the sealingelements, 'and also provides a matrix convenient to assemble.

The application of regenerators to gas turbines is generally understood.One example is described in U.S. Patent No. 3,077,074 of Collman et al.A discussion of the thermal distortion of such a regenerator matrix isto be found in U.S. Patent No. 2,888,2'48 of Bubniak et al. Structuresto minimize thermal distortion of the matrix are described in U.S.Patents No. 3,181,603 of Bubniak et al. and 3,186,479 of Mondt, and apreferred structure of a permeable heat transfer shim pack of such amatrix is described in U.S. Patent No. 3,183,963 of Mondt.

U.S. Patents 3,181,603 and 3,186,479 are directed to structures in whicheach of the labyrinth seal elements of the matrix is associated with anindividual beam or beams to reduce or minimize the warping or curvatureof the matrix including the labyrinth element'. Our invention isdirected to the same general objects as those prior patents but,according to our invention, a common stiffening or restraining structureis applied to a considerable group of sealing elements. Instead of adistortion resisting beam or pair of beams for each labyrinth element, arelatively small number of such beams are coupled to a considerablygreater number of labyrinth velements to provide the resistance tothermal distortion. The result is that space is available for aconsiderably greater number of labyrinth seal elements, thus providingfor a greater number Nice of labyrinth seal elements cooperating withthe fixed seal as the matrix passes through the bulkhead between the twofluids.

The structure according to our invention also facilitates compensationfor the greater circumference of a radial-flow matrix at the outsidethan at the inside, and leads to a structure which is relatively easy tofabricate and assemble.

The nature of our invention and the advantages thereof will be clear tothose skilled in the art from the succeeding detailed description of thepreferred embodiment of the invention and the accompanying drawingsthereof.

FIGURE 1 is a schematic diagram of a conventional radial-flow rotaryregenerator.

FIGURE 2 is a partial elevation view of the matrix with parts cut awayand in section.

FIGURE 3 is a sectional View of the matrix taken on a broken planecontaining the axis thereof as indicated by the line 3--3 in FIGURE 2.

FIGURE 4 is a partial axonometric view of the matrix with parts cutawayand in section.

Referring first to FIGURE 1, a radial-flow regenerator of usual type maybe considered to embody a housing 5 and an annular matrix 6. The matrixis rotated about its axis by means, not illustrated, so as to passthrough a bulkhead 7 at two places. Main seals 9 surround the matrixwhere it passes through the bulkhead to minimize leakage of fluid. Theseseals, as is well known, include shoes which lie in close proximity toor in light rubbing Contact with the inner and outer surfaces of thematrix to cooperate with labyrinth seal elements of the matrix.

In operation, a first fluid to be heated may be considered to enter thehousing at 10, flow inward through the matrix, and be exhausted throughan outlet 11. 'Ihe fluid which is to give up heat may enter the housingthrough an entrance 13 and leave through an outlet 14. Of course, thedirection of flow could be reversed. The details of such structure maybe generally as shown in U.S. Patent No. 3,057,604, No. 3,077,074, orNo. 3,267,674. The matrix 6 includes two ring-shaped rims 15, one ateach end of the matrix. The rims are structurally connected by asuitable number of parallel stiffeners 17 which are rigidly connected tothe rims. In the particular structure illustrated, there are twelve suchstiffeners equally spaced around the rim. The stiffeners are locatedwith respect to the rims by tenons 18 which project into acircumferential groove 19 in the inner surface of the rim. Thestiffeners are fixed to the rims by pins 21 driven into drilled andreamed generally radial bores 22 in the stiffener and 23 in the rim. Therims and stiffeners constitute a structural framework for the matrix.

To reduce thermal defiection of the stiffeners, each is made of twoprincipal parts; a radially outer bar 25, which is the structuralelement connecting the two rims, and a radially inner bar 26 whichserves as a space filler between the segments of the matrix on each sideof the stiffener. The inner bar 26 is mounted on the outer bar by twodowels 27 fitted in aligned bores in the two bars. Clearance is providedat the end of bar 26 for relative expansion.

A heat transfer segment 29 is mounted in each of the twelve spacesdefined between the rims and any two adjacent stiffeners 17. Each ofthese segments comprises a rather large number of packs of heat transfermaterial in the form of a number of laid-up thin corrugated sheet metalstrips or shims 31 which are preferably of the type described in U.S.Patent No. 3,183,963. These have zigzag corrugations, and haveanticonducton slits or perforations 32 through the shim. Four radialslots 33 in the shims allow core thermal growth without undue loading ofthe deflection control means.

Labyrinth seal elements 34 disposed between adjacent shim packs are ofsuch dimensions as to project slightly from the radially outer and innerfaces of the shim pack. The labyrinth elements have straight radialcorrugations as shown most clearly in FIGURES 3 and 4. These also are ofthin sheet metal. In a particular example, sheets 31 are of 0.002 inchstock and sheets 34 of 0.003 inch stock.

Each 30 heat transfer segment also includes a number of deflectioncontrol beams. Specifically, each includes three main control beams 35and two minor or end control beams 37. The end control beams lie againstthe stiffener, the radially outer portion of which is cut away on eachface as indicated at 38 to provide a recess for the beams. The controlbeams include bosses 39 and 41, respectively, which project into thegroove 19 in the inner surface of the rim. The heat transfer shim andlabyrinth seal elements also are provided with tongues, indicated at 42,which project into the groove 19. Thus, all of the elements of the heattransfer segment are located radially by the tongues or projectionsextending from them into the groove 19 in the rim.

The labyrinth seal elements34 and the control beams 35 and 37 arerigidly connected together by a bridge 45 extending from edge to edge ofthe heat transfer segment midway between the rims 15. This bridge, whichlies substantially in the plane of the outer surface of the heattransfer shim packs, fits into notches 46 in the main control beams, 47in the end control beams, and 48 in the heat transfer shims 31 andlabyrinth elements 34. The arcuate bridge 45 is brazed to these elements31, 34, 35, and 37. The ends of the bridge are slightly spaced from thestiffeners.

The remaining elements of structure of the heat transfer segment are tworetainer ring segments 50 which extend across the ends of all of theprojections or tongues 39, 41, and 42, and are brazed to the tongues ofthe labyrinth elements 34. These tongues extend slightly beyond thetongues of the heat transfer shims 31. These ring segments lit into thegroove 19 in the rim when the assembly is made, and serve to hold theparts of the heat transfer segment assembled before they are placed intothe framework of the matrix. They also prevent leakage past the ends ofthe tongues of the labyrinth elements.

It should be noted that the beams 35 and 37 extend only about fortypercent of the thickness of the matrix, and are thus relatively shallowin the radial direction. Also, they are relatively thick in thecircumferential dimension of the matrix as compared to the heat transfershim elements and the lseal elements, so that the temperature gradientin these beams is relatively slight and the thermal deflection thereforerelatively slight. These beams serve to locate the bridge 45 radially ofthe matrix, and the bridge 45 being brazed to the labyrinth elementslocates them radially at the mid-point of the matrix.

As will be apparent, more than one bridge 45 could be provided betweenthe rims. However, in the illustrative embodiment of the invention, onebridge only is preferred.

It should be further noted that the beams 35 taper radially so that theopposed faces of the beams are substantially parallel. These, therefore,provide for the radial convergence from outer diameter to inner diameterof the matrix without requiring any convergence of the other elements ofthe matrix. Note that the radially inner part of the heat transferstructure converges as indicated at 52 in FIGURE 2 from the inner edgeof the beam 35 toward the inner diameter of the matrix where the sealelements 34 which abut the beam 35 engage each other.

To assemble the structure of the matrix, the individual elements of eachheat transfer segments are stacked in a jig or fixture and put underpressure to obtain the desired total thickness or circumferential extentof the stack-up. The bridge 45 is then brazed to the heat transfershims, the labyrinth elements, and the beams. The ring segments 50 arebrazed to the tongues 42 of the labyrinth elements. The heat transfersegments may then be stacked on one rim which is disposed with its axisvertical and then the stiffeners and the other rim may be put in place,after which the pins Z1 are fitted to hold the entire assembly together.

Note that the beams and bridge resist and reduce deilection of the heattransfer body, the assembly of shim packs. This effect can beused in amatrix in which the projecting labyrinthelements are omitted. n

In the illustrated structure, the three main and two end beams of eachsegment control the deflection of the segment, having about thirtylabyrinth elements. Thus, each beam accounts for the restraint of aboutsix labyrinth elements. By virtue of r`this structure, the number oflabyrinths in a matrix of given size has been increased by a factor offour over previousdesigns, thus improving the efliciency of sealingandreducing pressure pulsations in the seals. Also, the control ofdistortion or deflection of the matrix is greatlyA improved, thedeflection being reduced to one-halfy that of previous metal matrices ofthe same dimensions. Thisreduction in deflection also con tributes toimprovement in sealing between the fluids on the opposite sideslof theregenerator bulkhead.

The detailed description of the preferred embodiment of the inventionfor the purpose of explaining the principles thereof is notto beconsidered as limiting or restricting the invention, since manymodifications may be made by the exercise of skill lin the artwithoutdeparting from the scope of the invention.

What is claimed'.v is: f

1. An annular Imatrix for a rotary regenerator comprising, incombination, Atwo coaxial rims, stffeners distributed around thecircumference of the matrix extending from rim to rim, andstructurallyconnecting the rims,

the rims and stiffeners defining spaces for heat transfer material, anda h'eat transfer segment mounted in each said space, each heat transfersegment comprising a plural number of deflection control beams extendingfrom rim to rim, coupled to the rims and distributed circumferentiallyof the segment, a bridge extending circumferentially of the matrixspaced from the rims and fixed to the beams, the bridge extendingsubstantially from stitfener to stiffener and terminating at thestiffeners, a number of labyrinth seal elements substantially greaterthan the number of said beams extending from rim to rim, the sealelement being fixed to the bridge between adjacent beams, and heattransfermaterial mounted between the seal elements, the heat transfermaterial being of a structure pervious to fluid flow.

2. A matrix as recited in claim 1 in which the matrix is of cylindricalform adapted for radial flow of fluid, the seal elements and the beamsextend substantially parallel to the axis of the matrix, and the bridgeextends circumferentially of the matrix intermediate the ends thereof.

3. A matrix as recited in claim 1 in which at least some of the beamstaperv radially so that the opposed faces of adjacent beams aresubstantially parallel.

4. An annular radial-flow matrix for a rotary regenerator comprising, incombination, two rims disposed at the ends of the matrix, stiffenersdistributed around the circumference of the matrix extending from rim torim and structurally connecting the rims, the rims and stiffenersdefining spaces for heat transfer material, and a heat transfer segmentmounted in each said space, each heat transfer segment comprising aplural number of deflection control beams extending from rimto rimcoupled to the rim, and distributed circumferentially of the segment, abridge extending circumferentially of the matrix spaced from the rimsand fixed to the beams, the bridge extending substantially from stilenerto stillener and terminating at the stiffeners, and a heat transfer packmounted between the beams, the heat transfer pack being of a structurepervious to fluid flow comprising sheet metal strips extending from rimto rim, the bridge being fixed to the heat transfer packso as to resistradial deflection of the pack.

5 6 5. A matrix as recited in claim 4 in which the matrix 3,301,3161/1967 Mason 165-10 X defines a circumferential recess for the bridgeand the 3,367,405 2/ 1968 Addie et al 165--9 bridge is mounted in thesaid recess.

ROBERT A. OLEARY, Primary Examiner References Cited 5 ALBERT W. DAVIS,Assistant Examiner UNITED STATES PATENTS Us. CL X-R.

3,294,156 12/1966 Beaufrere et al 165--10 X 165-10

